High-mobility nanocrystalline silicon thin-film transistors fabricated by plasma-enhanced chemical vapor deposition

Hydrogenated nanocrystalline silicon (nc-Si:H) films were deposited by using 13.56 MHz plasma-enhanced chemical vapor deposition at 260 degrees C by means of a silane (SiH4) plasma heavily diluted with hydrogen (H-2). The high-quality nc-Si:H film showed an oxygen concentration (C-O) of similar to 1.5x10(17) at./cm(3) and a dark conductivity (sigma(d)) of similar to 10(-6) S/cm, while the Raman crystalline volume fraction (X-c) was over 80%. Top-gate nc-Si:H thin-film transistors employing an optimized similar to 100 nm nc-Si:H channel layer exhibited a field-effect mobility (mu(FE)) of similar to 150 cm(2)/V s, a threshold voltage (V-T) of similar to 2 V, a subthreshold slope (S) of similar to 0.25 V/dec, and an ON/OFF current ratio of similar to 10(6). (c) 2005 American Institute of Physics.